The present invention relates to sealing devices and to packaging machines including same. A sealing means is known from, for example, German Pat. No. 2,323,409, issued to the present applicant, or from German Pat. No. 1,939,216 in which two tool portions are movable with respect to one another so as to close onto the work to be sealed. A sealing tool is disposed in one of the two portions and is adapted to be moved onto the work, and the other tool portion has an anvil surface against which the sealing tool pushes the work for sealing the same during the formation of the seal. The materials being sealed together are portions of thin materials, such as, for example, paper or foil webs, and the effect of the sealing is to enclose a container wholly or partly formed by the webs.
A sealing means of this kind may be used with packaging machines, especially vacuum packaging machines, such as are also known from the above mentioned printed publications. In such machines the anvil surface is formed of rubber and has a smooth surface. When the webs or foils are sealed, however, the problem arises that a plastic material web or foil contacting the anvil adheres thereto, to some extent, after the sealing operation. Such adhesion can be reduced by powdering the plastic material. However, with goods intended for medical use, such as, for example, syringes, powdering is impossible in view of the required degree of cleanliness. Furthermore, especially with respect to packaging objects of this kind, paper can be used as the cover of the container, and if adhesion of the plastic material to the anvil occurs, the freshly sealed joints between the paper and plastic materials are very easily torn.
Further representative art is disclosed in German Utility Model No. 1,802,886.